/*
NPlot - A charting library for .NET

Grid.cs
Copyright (C) 2003
Matt Howlett

Redistribution and use of NPlot or parts there-of in source and
binary forms, with or without modification, are permitted provided
that the following conditions are met:

1. Re-distributions in source form must retain at the head of each
   source file the above copyright notice, this list of conditions
   and the following disclaimer.

2. Any product ("the product") that makes use NPlot or parts 
   there-of must either:
  
    (a) allow any user of the product to obtain a complete machine-
        readable copy of the corresponding source code for the 
        product and the version of NPlot used for a charge no more
        than your cost of physically performing source distribution,
	on a medium customarily used for software interchange, or:

    (b) reproduce the following text in the documentation, about 
        box or other materials intended to be read by human users
        of the product that is provided to every human user of the
        product: 
   
              "This product includes software developed as 
              part of the NPlot library project available 
              from: http://www.nplot.com/" 

        The words "This product" may optionally be replace with 
        the actual name of the product.

------------------------------------------------------------------------

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;

namespace NPlot
{

	/// <summary>
	/// Encapsulates a Grid IDrawable object. Instances of this  to a PlotSurface2D 
	/// instance to produce a grid.
	/// </summary>
	public class Grid : IDrawable
	{

		/// <summary>
		/// 
		/// </summary>
		public enum GridType
		{
			/// <summary>
			/// No grid.
			/// </summary>
			None = 0,
			/// <summary>
			/// Coarse grid. Lines at large tick positions only.
			/// </summary>
			Coarse = 1,
			/// <summary>
			/// Fine grid. Lines at both large and small tick positions.
			/// </summary>
			Fine = 2
		}


		/// <summary>
		/// Default constructor
		/// </summary>
		public Grid()
		{
			minorGridPen_ = new Pen( Color.LightGray );
			float[] pattern = {1.0f, 2.0f};
			minorGridPen_.DashPattern = pattern;
			
			majorGridPen_ = new Pen( Color.LightGray );

			horizontalGridType_ = GridType.Coarse;
			
			verticalGridType_ = GridType.Coarse;
		}


		/// <summary>
		/// Specifies the horizontal grid type (none, coarse or fine).
		/// </summary>
		public GridType HorizontalGridType
		{
			get
			{
				return horizontalGridType_;
			}
			set
			{
				horizontalGridType_ = value;
			}
		}
		GridType horizontalGridType_;


		/// <summary>
		/// Specifies the vertical grid type (none, coarse, or fine).
		/// </summary>
		public GridType VerticalGridType
		{
			get
			{
				return verticalGridType_;
			}
			set
			{
				verticalGridType_ = value;
			}
		}
		GridType verticalGridType_;


		/// <summary>
		/// The pen used to draw major (coarse) grid lines.
		/// </summary>
		public System.Drawing.Pen MajorGridPen
		{
			get
			{
				return majorGridPen_;
			}
			set
			{
				majorGridPen_ = value;
			}
		}
		private Pen majorGridPen_;


		/// <summary>
		/// The pen used to draw minor (fine) grid lines.
		/// </summary>
		public System.Drawing.Pen MinorGridPen
		{
			get
			{
				return minorGridPen_;
			}
			set
			{
				minorGridPen_ = value;
			}
		}
		private Pen minorGridPen_;


		/// <summary>
		/// Does all the work in drawing grid lines.
		/// </summary>
		/// <param name="g">The graphics surface on which to render.</param>
		/// <param name="axis">TODO</param>
		/// <param name="orthogonalAxis">TODO</param>
		/// <param name="a">the list of world values to draw grid lines at.</param>
		/// <param name="horizontal">true if want horizontal lines, false otherwise.</param>
		/// <param name="p">the pen to use to draw the grid lines.</param>
		private void DrawGridLines( 
			Graphics g, PhysicalAxis axis, PhysicalAxis orthogonalAxis,
			System.Collections.ArrayList a, bool horizontal, Pen p )
		{
			for (int i=0; i<a.Count; ++i)
			{
				PointF p1 = axis.WorldToPhysical((double)a[i], true);
				PointF p2 = p1;
				PointF p3 = orthogonalAxis.PhysicalMax;
				PointF p4 = orthogonalAxis.PhysicalMin;
				if (horizontal)
				{
					p1.Y = p4.Y;
					p2.Y = p3.Y;
				}
				else
				{
					p1.X = p4.X;
					p2.X = p3.X;
				}
				// note: casting all drawing was necessary for sane display. why?
				g.DrawLine( p, (int)p1.X, (int)p1.Y, (int)p2.X, (int)p2.Y );
			}
		}

		/// <summary>
		/// Draws the grid
		/// </summary>
		/// <param name="g">The graphics surface on which to draw</param>
		/// <param name="xAxis">The physical x axis to draw horizontal lines parallel to.</param>
		/// <param name="yAxis">The physical y axis to draw vertical lines parallel to.</param>
		public void Draw( Graphics g, PhysicalAxis xAxis, PhysicalAxis yAxis )
		{

			ArrayList xLargePositions = null;
			ArrayList yLargePositions = null;
			ArrayList xSmallPositions = null;
			ArrayList ySmallPositions = null;

			if (this.horizontalGridType_ != GridType.None)
			{
				xAxis.Axis.WorldTickPositions_FirstPass( xAxis.PhysicalMin, xAxis.PhysicalMax, out xLargePositions, out xSmallPositions );
				DrawGridLines( g, xAxis, yAxis, xLargePositions, true, this.MajorGridPen );	
			}

			if (this.verticalGridType_ != GridType.None)
			{
				yAxis.Axis.WorldTickPositions_FirstPass( yAxis.PhysicalMin, yAxis.PhysicalMax, out yLargePositions, out ySmallPositions );
				DrawGridLines( g, yAxis, xAxis, yLargePositions, false, this.MajorGridPen );
			}


			if (this.horizontalGridType_ == GridType.Fine)
			{
				xAxis.Axis.WorldTickPositions_SecondPass( xAxis.PhysicalMin, xAxis.PhysicalMax, xLargePositions, ref xSmallPositions );
				DrawGridLines( g, xAxis, yAxis, xSmallPositions, true, this.MinorGridPen );
			}

			if (this.verticalGridType_ == GridType.Fine)
			{
				yAxis.Axis.WorldTickPositions_SecondPass( yAxis.PhysicalMin, yAxis.PhysicalMax, yLargePositions, ref ySmallPositions );
				DrawGridLines( g, yAxis, xAxis, ySmallPositions, false, this.MinorGridPen );
			}

		}

	}
}
